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redhotracing
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« Reply #75 on: February 02, 2012, 02:06:04 PM » |
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I talked to Joe Timney about this very thing while I was building the cage in a 98 Camaro.
His opinion was to not "sandwich" plates, but to attach route tubing through the plate,
then weld directly into a "frame" piece, such as 2x2 square tubing that is mounted under
the attachment and welded into the unit body. The tube could then be welded to the plate
as well, adding much for angular rigidity in the event of a crash, also making the OEM sheet
metal discussion negligible. If the car has an existing good cage, said "brace" could be welded
onto the existing plate/unit body structure, tying everything together. We used 2x2 .120 wall
under .250 plate, in lengths of 3 foot (or more where needed) to distribute load effectively.
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Luke- Winston Salem, NC
Red Hot Racing #9232
LTA 200 Club Member
Maxton- 192.323mph
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gearheadeh
Full Member
 Offline
Age: 50
Location: Calgary Alberta Canada
Posts: 216
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« Reply #76 on: February 02, 2012, 04:53:45 PM » |
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I talked to Joe Timney about this very thing while I was building the cage in a 98 Camaro.
His opinion was to not "sandwich" plates, but to attach route tubing through the plate,
then weld directly into a "frame" piece, such as 2x2 square tubing that is mounted under
the attachment and welded into the unit body. The tube could then be welded to the plate
as well, adding much for angular rigidity in the event of a crash, also making the OEM sheet
metal discussion negligible. If the car has an existing good cage, said "brace" could be welded
onto the existing plate/unit body structure, tying everything together. We used 2x2 .120 wall
under .250 plate, in lengths of 3 foot (or more where needed) to distribute load effectively.
Too confusing....Do you have some pictures please? |
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40 is the old age of Youth, 50 is the young age of the Senior years.
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redhotracing
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« Reply #77 on: February 02, 2012, 09:34:09 PM » |
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Basically, create a thru-body frame by welding 2x2 or 2x3 box tube
to the unit body subframe. Then weld the cage to this created "frame".
More structure, less relying on .035" sheet metal for strength.
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Luke- Winston Salem, NC
Red Hot Racing #9232
LTA 200 Club Member
Maxton- 192.323mph
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Kiwi Paul
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« Reply #78 on: February 04, 2012, 12:53:18 AM » |
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Actually, I was working with a guy on something like this today. The car is a Vintage SCCA type car that may be run at BVille eventually. Being an anemic Nash Healey, It won`t go fast, but the cage layout is interesting, and is all tied to a 2x2x120 underframe. It is all on the computer in a Solidworks type application, and the layout was able to be rotated and parts added/deleted. Pretty trick, and the tie ins and engineering looked good. Mostly 2'' by 120 wall tubing, which passes SCCA Tech. I would say that the car would be a perfect 150 Club example, so we`ll see what happens....
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McRat
Hero Member
Offline
Age: 52
Location: Norco CA
Posts: 1423
Diesel Hotrodder
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« Reply #79 on: February 04, 2012, 11:09:15 AM » |
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Just ramblin.
Tearing or cracking starts at little spots that don't show up in normal FEA models. A sharp edge, a minor gap in a weld, a small notch, etc. The narrower and deeper it is, the worst. Cracks start failures.
Square plates without large corner radii should fail at the pointy corners. Oval plates should be harder to tear with the same surface area. Modern epoxy should perhaps be stronger than welding when having to attach to thin wall material. Small areas of welding errors create stress risers. But doing a good job of gluing isn't easy. For those who don't know, modern aircraft are often glued together, and IIRC, so are newer Ferrari's.
When we did our our cage we had to to the body for 2 bars. So we made the bars redundant. We Y-tubed the main hoops so it attaches in 2 planes, and then put in kick bars to attach the bottoms, then extra 45° bars to do the job of the two bars attached to the body. The back bars (attached to body), are not adding any strength at that point. The NHRA allows you to remove those bars IF YOU do extra bracing as of 2008(?).
However, our truck is "heavy" compared to a car. So the extra tubing made sense, even if it hurts our drag race ET's, it will be much stronger than the minimums, perhaps twice as strong.
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Pat and Kat McSwain - DT 1616 "Casper" 2005 GMC 2500HD Sierra 4x4 Duramax Diesel + Allison Transmission B/DT & A/DT record holder, El Mirage (163) & Bonneville (175) Best clocking 197.068 mph - Bonneville '09, 2.25mi www.duramaxdiesels.com |
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redhotracing
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« Reply #80 on: February 05, 2012, 02:19:29 PM » |
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Wolfe Racecraft makes nice thru-body subframe connectors for our application,
we used it as a template for SFC's, seat mounts and cage mounts.
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Luke- Winston Salem, NC
Red Hot Racing #9232
LTA 200 Club Member
Maxton- 192.323mph
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NathanStewart
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« Reply #81 on: February 11, 2012, 04:15:28 AM » |
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Here they are: Please no comments on the weld quality or anything else. The car owners graciously let me take these pictures to help me. Pictures are only to demonstrate the rule book requirement of 1/4" base plates. The floor they are welded to is .035" sheet metal. Is this the best solution?
Don't want to get into the details about the car or the owner or whatever but I would like to know what kind of car this is (make and model?). |
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